# Math Help - I'm a dunce

1. ## I'm a dunce

This question is giving me a headache, and it's for homework. I usually can do these kinds of questions, but I feel really unmotivated right now.. Someone can help me solve it so I can see again..

Find the equations of the focal chord that cuts the curve x^2=8y at (-4, 2)

2. Hello, Cataclysm!

If you made a sketch, the answer is obvious . . .

Find the equation of the focal chord that cuts the curve $x^2\:=\:8y$ at (-4, 2)
From the equation, $x^2 \:=\:8y$, we know all this:
. . The parabola opens upward.
. . Its vertex is at the origin.
. . The focus is at (0, 2).

Code:
                |
*          |           *
|
*        F|(0,2)     *
(-4,2)*- - - - o - - - -*
*      |      *
*   |   *
------------*------------
|

The focal chord that contains (-4, 2) is the horizonal line: . $y \:=\:2$

3. Yeah, that's what I thought it was, but I just couldn't explain myself properly. Thanks very much!